1. Field of Invention
The present invention relates to a process for using specific silicone phosphate esters in personal care applications, where the proper selection of the phosphate ester allows for (a) maximum foam, (b) minimum irritation and (c) optimum skin feel. The process relies upon the selection of a specific type of silicone phosphate ester. The proper phosphate ester: (a) is a mono-esters made by phosphation with polyphosphoric acid, (b) contains between 45 and 60% polyoxyethylene in the molecule by weight, (c) has between 6 and 15 phosphate groups, and (d) has free hydroxyl groups present in the molecule.
When this combination of structural attributes are preset, an aqueous cosmetic formulation can be made which is (a) clear, (b) high foaming and (c) conditioning to the skin and hair, without building up.
2. Object of the Invention
It is the object of the present invention to provide a process for using specific silicone phosphate esters in personal care applications, where the proper selection of the phosphate ester allows for (a) maximum foam, (b) minimum irritation and (c) optimum skin feel. The process relies upon the selection of a specific type of silicone phosphate ester. The proper phosphate ester: (a) is a mono-esters made by phosphation with polyphosphoric acid, (b) contains between 45 and 60% polyoxyethylene in the molecule by weight, (c) has between 6 and 15 phosphate groups, and (d) has free hydroxyl groups present in the molecule.
3. Description of the Arts and Practices
Silicone oils (polydimethylsiloxane) have been known to be active at the surface of plastic, cellulosic and synthetic fibers as well as paper. Despite the fact that they are lubricants that are stable to oxidation, their high cost and lack of durability has made them cost prohibitive in most application areas. Silicone oils need to be emulsified prior to application. This requires high-pressure equipment, surface-active agents and generally results in a milky emulsion. Emulsions have experienced stability problems both in terms of freeze thaw instability and upon heating. This has resulted in minimal acceptance of them in commercial products.
U.S. Pat. No. 5,070,171 issued Dec. 3, 1991 to O""Lenick, incorporated herein by reference, describes a variety of silicone phosphate esters. These products are described as being useful in a variety of applications, from fiber and textile lubricants, to alkali stable products. We have surprisingly learned that the compounds of the O""Lenick invention can be modified to produce products with the desired properties for personal care applications where aqueous products that are (a) clear, (b) high foaming and (c) conditioning to the skin and hair, without building up are achieved.
U.S. Pat. No. 5,859,161 to Imperante et al issue Jan. 12, 1999, teaches that phosphate esters can be used to migrate irritation in sulfated surfactants.
None of these patents suggest that by selecting the proper silicone phosphate, a clear, high foaming, highly conditioning solvent free aqueous product could be prepared.
The present invention relates to a to a process for using specific silicone phosphate esters in personal care applications, where the proper selection of the phosphate ester allows for (a) maximum foam, (b) minimum irritation and (c) optimum skin feel.